This invention relates in general to mechanical face seal assemblies. In particular, this invention relates to a seal head subassembly for use with a seal seat subassembly for a mechanical face seal.
A mechanical face seal assembly provides a fluid seal between a housing member and a shaft, one of which is rotating with respect to the other. Typically, the housing member is stationary and the shaft is rotating. The seal assembly prevents fluid loss between the shaft and the housing. One example of a mechanical face seal is disclosed in U.S. Pat. No. 5,676,382.
Conventional metal bellows seal assemblies have included designs which required complex fixtures and operations to crimp elements together. Furthermore, conventional designs have required machining to a seal ring to correct distortions that can occur in a crimping process. Other elements of such designs required bonding to retain elements together. Also, heat was retained in convention bellows seal assemblies that encapsulated and insulated seal rings. Such heat can cause distortions and possible leaks.
The present invention includes an improved mechanical face seal. The mechanical face seal includes a seal head subassembly and a seal seat subassembly. The seal head subassembly includes a direct drive mechanism between components of the subassembly to prevent relative rotation between mating elements. The seal head subassembly also avoids distortion of a seal ring during an assembly process, thus eliminating the need to machining. Furthermore, the seal head assembly exposes a substantial amount of the seal ring, so that heat can be dissipated without causing distortion to a seal ring.
In a preferred embodiment, a seal head assembly includes a case. A ferrule is seated against the case. A spring is seated at one end against the ferrule. A spring seat receives a second end of the spring. The retainer ring has a band and a plurality of tabs, wherein the band engages the spring seat. A metal bellows has a first end in contact with the case and a second end having a contact surface for the tabs of the retainer ring. A seal washer has an annular groove, wherein the seal washer is received in the second end of the metal bellows. A seal is received in the annular groove of the seal washer.